The objective of the HiFIVE program is to develop an integrated, microfabricated vacuum electronic (VE) high-power amplifier (HPA) circuit for use in high-bandwidth, high-power transmitters. Additionally, the program will demonstrate operation of such a circuit over a 5 GHz frequency band centered at 220GHz. The HIFIVE program is pursuing innovative technologies and approaches in several areas to overcome critical technological barriers in order to enable an integrated, microfabricated vacuum electronic (VE) high power amplifier (HPA) circuit. The first area focuses on the development of the necessary circuit elements to achieve a compact high-performance 220GHz VE HPA. The second area focuses on the design and construction of the high power amplifier and its demonstration.

The HiFIVE program will consist of three phases. The first phase will focus primarily on HPA design, development of a method for achieving stable, high-power electron beam transport, and microfabrication of the interaction structure. Development of an advanced, high-current density, integrable cathode will be initiated in this phase. The second phase will focus on validating the HPA design and the continued development of the high-performance cathode. It will culminate in a demonstration of its ability to operate without degradation for at least 103 hours. The third phase will involve the construction and test of an HPA incorporating the advanced cathode as well as other critical circuit elements assembled into a compact, integrated structure. (Source http://www.darpa.mil/MTO/programs/hifive/index.html)